Some single phase induction motors depend on the use of a start winding which is located ninety electrical degrees from the run winding in order to develop sufficient torque to accelerate the motor up to running speed. The start winding is ordinarily designed for short term use which necessitates that the winding be removed from the circuit when the motor comes up to speed. This is usually accomplished by installing a stationary switch and a centrifugal actuator. The actuator to which this application is directed employs the use of hinges which enables the weights to move from a start position to a run position by a pivoting action rather than a sliding action along the base. The actuator of the invention utilizes a base of magnetic material to enclose the weights on a minimum of three sides of an envelope around the weights which diverts magnetic flux from the motor away from the weights and this minimizes the effect of magnetic flux on switching speed. The actuator of the invention also has preloaded tabs which are an integral part of the base and preloaded recesses which are an integral part of the hub and these are designed in a manner so that the preloaded recesses and tabs develop sufficient force on the hub to prevent the hub from rattling on the shaft as the motor coasts down and the hub contacts the stationary switch. The preloading of the tabs and recesses is provided by a pair of springs which extend diametrically on each side of the actuator.